This fixes following compile error seen when
building mac80211 with mesh disabled:
.../backports-5.15.58-1/net/mac80211/agg-rx.c: In function 'ieee80211_send_addba_resp':
...backports-5.15.58-1/net/mac80211/agg-rx.c:255:17: error: 'struct sta_info' has no member named 'mesh'
255 | if (!sta->mesh)
| ^~
sta_info.h shows this item as being optional based on flags:
struct mesh_sta *mesh;
Guard the check to fix this.
Fixes: f96744ba6b ("mac80211: mask nested A-MSDU support for mesh")
Signed-off-by: Koen Vandeputte <koen.vandeputte@citymesh.com>
45109f69a6